Apparatus and method for filling gas storage cylinders



Nov. 19, 1946. G. H. SMITH 2,411,235

` APPARATUS AND METHOD FOR FILLING GAS STORAGE CYLINDERS Filed Febfll, 1945- 5 Sheets-Sheet l INVENTOR GEORGE H. SMITH ATTORNEY Nov. 19, 1946. '(3, 'HQ SMH-H ATPARATUS AND METHOD FOR FILLING `GAS STORAGE CYLINDERS 5 Sheets-Sheet 2 l? l L .I

vFiled Feb. ll, 1945 -IIIIII AUTOMATIC CHARGING EQUIPMENT CYCLE TOPPING OFF WITH RISING PRESSURE TIME I c mw N E wm naso.. .LNDG o l N IASW mm meca V lnIvENroR GEORGE H. SMITH ATTORNEY G. H. SMITH 2,411,235

APPARATUS AND METHOD FOR FILLING GAS STORAGE CYLINDERS Nov. 19, 1946.

Filed Feb. 11, 1943 5 Sheets-Sheet 3 NVEN'OR GEORGE H.` SMITH ATTORNEY 5 Sheets-Sheet 4 G. H. SMITH Nov. 19, 1946.

APPARATUS AND METHOD FOR FILLING GAS STORAGE CYLINDERS Filed Feb. l1, 1943 n .web RSS m Nov, 19,1946. l G, H, SMH I 2,411,235

APPARATUS AND METHOD' FOR FILLING GAS STORAGE CYLINDERS Filed Feb. 11, 1943 5 Sheets-Sheet 5 l l Nron GEOR H. SMlTH ATTORNEY This invention relates Patented Nov. 19, 1946 APPARATUS AND METHOD FOR FILLING GAS STGRAGE CYLINDERS George H. Smith, Kenmore, N. Y., assigner to The Linde Air Products Company, a corporation of Ohio Application February 11, 1943, Serial No. 475,567

(Cl. 22S-20.1)

Claims. l

to a method of and apparatus for charging gas storage containers and more particularly to filling gas storage cylinders to a desired nal pressure with valuable gas material, such as oxygen, nitrogen, hydrogen, helium, argon, or the like.

The main object of the invention is to provide apparatus for filling gas storage cylinders that is compact and so light lnvvelght that it may be mounted on a mobile unit, such as an automotive truck which is adapted to transport the gas material in the liquid phase to the station at which the gas storage cylinders are ,to be lled. Another object of the invention is to provide an improved system for rst evacuating and then filling cylinders including equipment that is substantially automatic in its operation and in which the cylinders are connected tobe filled and disconnected after being filled in a sequence such that the maximum eiiciency of the equipment and of an operator is obtained.

.a further object is to provide an improved method of filling gas storage cylinders to a desired final pressure.

The invention comprises a four-rack two-cylinder system having a capacity of at least 100 cylindesper hour. Such system comprises simple and reliable means for nlling any number of cylinders to the.`correct settled pressure and which is capable of carrying out the operation at a rate equivalent to the output rate of a high pressure liquid pump. In order to charge all of the cy1in ders within a predetermined range oi a desired final pressure, the present invention contemplates a procedure termed a topping ofi cycle with a slowly changing pressure, whereby, for example, a small volume of gas is added to the cylinders at a comparatively low rate of flow after they have been charged rapidly to a pressure near, such as slightly below, the desired nal pressure.

ln general, according to the invention, the gas storage cylinders are filled progressively in pairs, the operating cycle of the system being such that, while four cylinders are being evacuated, two are being lled and two are being changed. There is, however, `some overlapping of these operations.

Referring to the drawings:

Fig. l is a perspective view of a four-rack twocylinder unit for charging gas storage cylinders with gas material, embodying the invention;

Fig. 2 is a circuit diagram of the electrical control system;

' Fig. 3 is a graphical representation of the timing operations involved in lling gas storage cylinders according to the invention;

Fig. 4 is a ilow diagram illustrating the invention;

Fig. 5 is a fragmentary view partially in front elevation and partially in vertical section of the valve timing mechanism. taken on line 5 5 of Flg. 6;

Fig. 6 is a fragmentary view partially in top plan and partially in horizontal section, taken onI line 5-5 of Fig. 5;

Fig. 'T is a fragmentary view in vertical section, taken on line l-l of Fig. 6;

Fig. 8 ls a fragmentary view mainly in top plan, taken on line B- of Fig'. 5;

Fig. 9 is a `fragmentary view mainly in rear elevation. taken on line 9 9 of Fig. 6; and

Fig. 10 is a fragmentary view in horizontal section, taken on line idw-ll) of Fig. 9.

Referring to Fig. 1 of the drawings, the illustrated four-rack twofcyllnder unit comprises a metal frame lil adapted to be mounted cna suitable vehicle, such as anI automobile truck, although the apparatus is not restricted to use in a mobile ,cylinder charging unit. The frame l consists of metal sections which are welded to` gether to form a light-weight structure generally in the shape of van open rectangle having a base ll, uprights l2 and i3, andsides it, Ml. Supported by a bracket l5 on the top of the frame it are four gas manifolds or racks A, B, C and D, each of which is provided with a pair of 'flexible metal tubing pigtails iti. Each pigtair terminates in a Quick connector il for connection to the valve iitting i5 (Fig. 4) at the top of a conventional gas storage container le such as a cylinder in which oxygen in the gas phase is usually stored at an initial gas pressure of a predetermined value.

Laterally projecting members 25, '2l and 22 are mounted on the sides it of 'the frame l0 to locate the cylinders i9 in pairs on opposite sides of the frame, as indicated by the stations or places 23 corresponding to the racks A, B, C and D. Each of the racks is provided with a gas pressure gauge or indicator 213 mounted thereon. Also mounted on each rack is an electric signal lamp 25 for indicating when the cylinders connected to the rack are nlled with eas at the desired final pressure.

In about the center of the frame it, between the sides it, le thereof is mounted a cylindrical housing 2li on a box 2'? which is, in turn, supported by a bracket E. A main operating shaft 23 having a handle H, extends down through the center of a heavy main spring K (Fig. 5|) in the form of a coil Within the housing 26, the upper 3 end ofthe spring being connected to the shaft 28, and the lower end being connected to a collar L which is keyed to -a gear M and the top half O,

(Fig. 7) of a clutch loosely mounted on the shaft ization valves 35 (Fig. 4) in the box 21 from one assises oxygen vproduced by .conversion of liquid oxygen to the gas. phase by a high-pressure pump and vaporizer apparatus the outlet of which is connected to a filling line 54 (Fig. 4) having Van accumulator 55 connected thereto by a valve 58. Also connected to the filling line 55 is al highvpressure safety valve 51 and a high-pressure gauge 51'. The line 54 is connected to a Y-fltting 58 one branch of which is connected tothe pipe 53 and the other branch of which is connected to a pipe 59 containing a metering orifice sure by a pipe 93. Such source may be gaseous 58, such as a valve, and a shut-off valve 5| which rack to another (there being a blowdown valve 34 and an equalization valve 35 for each of the racks A, B, C and D) whenever the spring shaft 28 is rotated.

A latch P pivoted to one side of the housing 26 and urged downwardly by a tension spring 36 engages a slot 36 in a collar I pinned to the .equalization valve stem 3|, every 90 degrees of rotation, thus locking the spring shaft 28 in position. The latch P is adapted to permit the shaft 28 .to be advancedy clockwise but notcounter-clockwise. The gear M which is keyed to the upper half O of the clutch meshes with a gear 31 pinned to an evacuation valve stem 38 which is geared to a filling valve stem 39 by gears 49 and 4|, sothat,such valve stemsrotate when a latch Q restraining the spring force is released and the lower end only of the spring K is allowed to turn. The latch Q is pivoted at 42 4to one side of the housing 26 and is provided with a projection 43 adapted to engage a slot 44 in a collar J attached tothe filling valve stem 39, under the influence of a tension spring 45, oonnected at .one end to the latch Q andat the other to the frame base is operated by the solenoid 58 (Fig. 2), the armature 62 of the latter being operatively connected to the valve 6| by a lever 63.

The outlet ofA the back-pressure valve 52 is connected by a pipe 54 toI four filling valves 55 (Fig. 4) within the box 21 (Fig. 10) which are operated insequence byrotation of the fillingvalve stem 39 through a suitable cam device;

each valve 55 controlling the .flow of /gas to e, rack.

Each rack is also provided with an evacuation valve 65 in the box 21, which is operated by a cam device upon rotation of the stem 38. j

The four equalizing valves are connectedfbe- Vtween the racks and an equalizing line 51 (Fig.

' sure in the line l61 reaches a predetermined value The clutch is Aconstructed so that thel lower half R can be rotated 90 degrees in a clockwise direction while the top half O is locked in astationary position by the latch Q, an operation which is perfumed at the end of a cylinder topping oif period. When the latch Q is released at the end `of a rapidcylinder' filling period. the force of main spring K then causes the upper half of the clutch also-to rotate 90 degrees in a a. cam N mounted above Ithe housing'26 (Fig. 8)

for operatingfnormally-open signal light contacts SA, SB, SC and SD. These, contacts are simple micro-switches mounted on the top of to close a switch 69 (Fig. 2) and thereby cause the solenoid 49 to be'energized. The solenoid 49 has an 'armature 1li adapted, when raised, to

' close a small 'micro-switch X having a contact 1| which is in circuit relation with the battery '5`|, normally-closed contacts 1| and 41, and solenoid S. 'Ifhe armature 46, when lifted, opens contacts1| and 41, and closes contacts 'I2 which are in holding circuit relation with solenoid S, as

well as contacts 48 which are in circuit relation with the solenoid 50 and battery 5|. The armature 62, when raised, is adapted to close the valve the cover of the housing-25, whi h are operated by the force of the cam N when -the shaft 28 is turned. Also connected to the shaft 28 is a cam G (Fig. 2) for closing electrical contacts 41 and -opening electrical contacts 48, thereby de-energizing a solenoid 49 and a solenoid 50 (Fig. 2),

to reset the electrical circuit when the handle H vis moved through a 90 degree arc.` A battery 5| is mounted within the bracket E, and provides a source of electrical energy for such circuit, al-

though the battery of the vehicle on which the frame I0 is carried may be and preferably is terial at constant temperature under high pres- 5|, and close` contacts Z in holding circuit relation with the-battery 5| and solenoid 49,- solenoid 50, and one set of the signal lampcontacts SA. i

A rack safety device 13 is connected to each rack and is adapted to open should the gas presevacuation valves 55 and to a vacuum line 16 which communicates with any suitable evacuating meanssuch as a vacuum pump. A mercury manometer 11 and a lubricant'trap 18 are also connected to the vacuum line 16, with a valve 19 therebetween. Y

An automatic temperature controlling device is associated-with the gas supply or filling line 54 for the purpose' of maintaining the tempera-` ture of the gas delivered to the cylinders |9 at a substantially constant value. The device8|i come prises a cold-liquid or cold-gas inlet 8| connected to a valve body 82 to which is connected a hot-gas inlet 84. Gas leaves the device 80 by way of a gas outlet 98. l

Assuming that the device 80 is adjusted to a desired value of temperature, the device automaticallyv operates to maintain the temperature of the gas leaving the outlet 98 substantially constant at such value.

1n operation,- assuming that eight cylinders I9 are connected to the apparatus, two on each of, the Your racks A, B. C and D, the operating cycle generally is such that the cylinders are iilled in pairs, there being pairs o f cylinders on either si de of the unit as indicated in Fig. 1. The charging is done in such manner that the operator works progressively around the frame I in a clockwise direction. Briefly, the manual operations consist 4oi! i I (1) Closing two cylinder valves immediately after a signal light flashes;

(2) Turning the operating handle H in an arc of 90 degrees so that the handle H is above the cylinder valves just closed, and

(3) Disconnecting the illled pair of 'cylinders from the rack and replacing them with empty cylinders. The operator then steps tothe next pair of cylinders, in a clockwise direction, and

repeats the above operations when the next signal lamp 25 lights.

As shown by Fig. 3,- each pair of cylinders connected to the apparatus is subjected to the iollowing operations which are described, for example, for filling` oxygen cylinders of the customary size: The cylinders are evacuated, illled,

vtopped oi, and then removed from the rack.

Rapid iilling of the cylinders is accomplished at a constant ratel which is such that many cylinders can be filled per hour. As soon as one pair of cylinders has been rapidly filled to a predetermined pressure, the filling of another pair is started. Since Vthe lling can be accomplished in one-half the time required for evacuation, two pairs of cylinders are filled while one pair is being evacuated. The timing of these operations is shown graphically in Fig. 3, where the operations carried out simultaneously with respect to the four racks are also indicated. As shown by such graph, while one pair of cylinders is being rapidly filled, a 'second pair is completing its u nal period of evacuation, a third pair is completing its initial period of evacuation, and the fourth pair is being topped oi and replaced with empty cylinders. l

In the apparatus shown in the drawings the method of topping of! the cylinders is accomplished by bleeding a small quantity of gas into the cylinders after the filling control valve has been closed, controlof the iinal pressure being accomplished with a slowly rising cylinder pressure.

I'he actual manual operations in the present method of iilling gas storage cylinders do notrequire more than a short time to carry out. Therefore, after the cylinders have been changed, there is a shorter period when no manual work is being done. During this time, the operator is free to inspect the cylinders. After an operator has become familiar with the apparatus, such inspection period may be'increased. v e

It should be noted that` there are four valves 34, 35, 65 and 66 (Fig. 4) for each of the four cylinder racks A, B, C and D. l These sixteen valves Aare geared and mechanized in pairs (Figs. 5, 6

through the electricshut-offzvalve 6I because the pressure on the inlet side of this valve 6| isfmain tained higher than the cylinder pressure atv all times by the back-pressure valve 52. The :rate of now Vthrough the shut-ofi valve 6I into the cylinders I9 is maintained at a low value by the orice 68 in the pipe 59.

During the topping-on' operation the pressure inside the cylinders I9 is nearly equal to that in the rack because the rate of iiow through the cylinder valves is comparatively low. When the mercury column in the gas pressure gauge 68, which is attached to the discharge side of the shut-oi! valve 6l, increases to a certain height, it makes an electrical contact with an adjustable pointer located inside lof the mercury column,

which is conventionally shown in Fig. l2 as a nor-l mally-open switch 69. Closure of the switch S9 results in the closure of the shut-ofi valve .BL stopping all gas iiow into the two cylinders being toppedoff; and the energization of the corresponding signal light 25. The operator then closes the two cylinder valves and turns the operating lever H which: (a) closes the equalizing valve 35 to rack A; (b) opens momentarily the blowdown valve 34 of rack A: (c) opens the equalizing valve 35 and the shut-ofi valve 6l to rack B; (d) cocks the main spring K within the housing 26 subse- After the above operations have been carried out, the gas pressure gauge 68 registers the pressure in rack B, the cylinders on which arenow being lled at a high rate of flow. As the cylinders connected to rack B are charged, the rack pressure rises rapidly, and when the mercury column again reaches the electric contact point (closing switch G9) another electrical circuit is completed which releases the main operating spring K, causing the lling valve 65 to racli B to close simultaneously with the closing of the evacuation valve 66 for rack C. This process is repeated for each of the four racks in rotation until the desired number of cylinders has been charged.

Assuming that eight cylinders I9 are connected to the apparatus, that the system is in continuous operation, and that the empty cylinders have just been attachedto the rack D, the following conditions exist:

(1)` The cylinders connected to the rack A are being charged rapidly through both the filling and equalizing valves and 35;

' (2) The cylinders connected to rack B are in the second period of being evacuated and are the next to be filled;

(3) The cylinders connected to rack C are in the first ,period of being evacuated; v

(4) The cylinders connected to the rack D are idle;

(5) The operator is standing in front of the cylinders connected to the rack A waiting until the iilling of these cylinders is completed. This will be indicated when the red lamp .25 connected tothe rack A is illuminated. Y

During the charging of the cylinders connected to the rack A, the mercury column in the gas pressure gauge 68 rises, indicating the pressure in rack A, since the gauge 68 is attached to the'pipf ing 61 on the rack` side of the electric shut-oil ing the latch 43 on the lever Q from the slot 44 in the lling valve stem collar J. Sincey the illling valve stem 39 is geared to the evacuating valve stem 38, which in turn is geared to the shaft 28 of the main operating spring K, releasing the latch 43 allows the lling and evacuating valve stems 39 and 38 to rotate 90 degrees, thus closing the filling' valve 65 to rack A and .opening the lling valve 65 to rack B, as shown in Fig. 3. Rapid charging of the cylinders connected to the rack B is then begun.

The 90 degree rotation ofthe evacuating valve stem 38 causes the evacuation valve 66 to rack B to close, and opens the evacuation valve 66 to rack D. The evacuating valve 66 to rack Cremains open during such operation.

As the rapid lling of the cylinders connected to the rack B begins, the cylinders connected to contact (switch 69) inside the tube, the switch 69 is closed, thereby `energizing solenoid 49. The action of this solenoid operates the small microswitch X, closing contact 1I', which energizes solenoid Slthrough the closed contacts 1| and 41. The operation of the armature .46 lifts the lever Q which releases the cam shaft collar J'and allows the filling and evacuating valve stems to turn the rack A are being topped off. This is accom- A, as shown in the flow diagram, Fig. 5. Since the gauge 68 still registers the pressure in rack A, the mercury column drops somewhat below the contact point after the filling valve 65 is closed because the rack pressure equalizes with the lower pressure in the cylinders. During rapid charging the cylinder pressure is lower than the rack pressure by an amount equal to the pressure drop across the cylinder valves and pigtails I6. As the gas flows into the rack B through the electric shut-olf valve 6l, the mercury column again rises slowly until it touches the contact pointer a second time. This second contact or closure of switch 69 results in the energzation ofl the solenoid 50, Fig. 2, which closes the electric valve 6I in the equalizing line 59, and in addition, energizes the signal light on rack A, indicating that the topping off of the cylinders connected to rack A has been completed.

When the signal light 25 connected to rack A flashes, the operator performs Vthe following operations: y

(1) Closes the valves on the cylinders connected to rack A;

(2) Pulls the operating lever H, Fig. l, through an arc of 90 degrees to a new position such that the lever H is over the cylinders connected to rack A;

through 90 degrees by spring action.

The operation of solenoid S also causes the contacts 'H and 4l to open, and closes contacts 'I2 and 48. The solenoid S is then energized through the contacts 12. When the mercury falls away from the pointer (switch 69), the contacts or switches 69, 'Il' and I2 are opened while contact 48 remains closed until cam G is manually operated by means of shaft 28 and handle H to open switch 48 and close switch 41 i' contact H is closed; solenoids 49 and S are de-energized, and the projecton 43 on the latch Q falls into the next slot 44 in the collar J.

After the operations described above, two new .cylinders are being charged rapidly through the filling line and the two cylinders just filled are being topped off through the shut-off valve and equalizing line. As these cylinders are being topped oil?, the mercury column again rises slowly until it again touches the pointer in the glass tube, thus closing the switch 69 a second time. This again energizes solenoid 49, closing contact 1I' and energizing solenoid 50 through the closed contacts Il and 48. The armature 62 of solenoid then closes the shut-off valve 6 I, stopping all flow of gas into the cylinders and terminating the topping off period.

As the solenoid 50 is energized, one of the four signal lights 25 is also energized through the switch SA, which is being held closed by the cam N on the main spring shaft 28 (this shaft 29 is rotated manually later, after the cylinders are closed off). Also, as solenoid 50 energizes, the contact Z is closed. This causes the solenoids 49 and 50 and the signal light to remain energized even though the mercury column falls away from the pointer inside of the glass tube, opening the switch 69.

(3) Disconnects the cylinders from rack A and cury column with. the pointer inside the glassl y tube;

(3) Manual operation of the handle H through 9() degrees. The automatic operations resulting from each of such steps are described below:

After the operating lever H has been rotated l through 90 degrees, one pair of cylinders is being lled rapidly through both the lling and equalizing lines. At this time, the electric circuit, which preferably operates at a certain potential, is in the condition indicated by Fig. 2. When the mercury column rises to a point where it touches the When the signal light 25 ashes, the cylinder valves are first closed off and then the operating lever H must be rotated clockwise through degrees. Such rotation of this lever H performs the following operations:

(1) Turns the main operating shaft 28, which extends down through the center of the heavy coil spring K within the housing 26, Fig. 1. Since the upper end of the spring ispinned to the shaft 28, and the lower end is being held rigidly in place through the filling and evacuating valve gearing by the latch Q on the slotted collar J, the main spring is cocked as the shaft 28 is turned.

The latch P, which falls into the slotted collar I on the equalizing valve cam shaft 3l locks the spring sha-ft 28 inthe new position.

(2) Rotates through 90 degrees the blowdown valve cam shaft 30, which is directly geared to the spring shaft 29, thus blowing down the pressure in the racli just filled, to the atmosphere, relieving this pressure before the cylinders are removed from the rack. This safety feature prevents deformation of the pigtail connections, such as would occur with high pressure in the rack, when the couplings are quickly. detached from the cylinders.

(3) 'Rotates the equalizing valve cam shaft 3l, which is geared to the blowdown valve cam shaft 30, through 90 degrees, thus closing the equalizing valve 35 to the full rack and opening such valve to the rack being iilled.

(4) Opens the signal light contacts SA, Fig. 2, on the rack just lled and closes the signal light contacts SB to the next rack.

(5) Closes the electrical contacts d1 by means of the cam G, and opens the electrical contacts 48, thereby deenergizing the solenoids t9 and 50. This opens contacts 1I thus resetting the electric circuit so that all contacts are again as shown in Fig. 2, except that the contacts SB are closed and contacts SA are open. lThe shut-ofi` valve 6| to the equalization line 6T is then open to the next rack being filled. i

The arrangement of gears between the main operating spring shaft and the four valve stems is shown in Figs. 1, 6, '7 and 8. At the end of each topping off period the lower half R of the clutch is rotated Whenever the spring shaft 28 is turned through 90 degrees. Since the blowdown and equalization valvestems are geared together, these two stems rotate, changing the valves from one rack to another, whenever the spring shaft is rotated. The latch P engages a slot on the collar pinned to the equalization valve stem 'every 90 degrees of rotation, thus holding the spring shaft 28 in position. The latch P is such that the shaft 28 can be turned clockwise but not counter-clockwise, as pointed out above.

Since the evacuation and lling valve stems are geared directly together, these two stems will rotate when the latch restraining the spring force is released and the bottom end of the spring only is allowed to turn. The position of the latch Q, in the slotted collar J, attached to the filling valve stem is shown in Fig. 2.

v half of the ciu-tch also to rotate 90 degrees in a clockwise direction, thus bringing the two halves O, R of the clutch assembly back to their original positions.

The apparatus is compact and entirely suitable for mobile use, the valve assembly including the sixteen valves being located in the box 21. For safety reasons all parts in contact with oxygen gas are made of non-combustible materials.

Thus, all materials used in the construction of the valve assembly are preferably metals except the Valve stem packing which is preferably asbestos and graphite. At the same time the ap- .paratus is suiiiciently compact and of such light weight that it may be mounted on a mobile pumping unit. The novelV topping-off operation resuits in a substantially uniform final pressure in the filled cylinders.

The topping-off period which follows immediately after the cylinders have been rapidly charged to a predetermined pressure permits the gas to flow slowly into the cylinders until the correct pressure is obtained. This relatively slow rate cf flow reduces the errors caused by varying 'time lags in the valve operating mechanism and the differences in unal cylinder pressures resulting from variation in the pressure drop through the cylinder valves at high rates of ow.

What is claimed is:

l. lapparatus for filling gas storage cylinders comprising, in combination, a plurality of' cylinder racks, cylinder evacuating means including means for selectively connecting at least two of said racks to a vacuum pump; cylinder filling means including means for selectively,r connecting at least one of said racks to a source of gas material under pressure; rack blowdown means including means for selectively opening at least one of said racks to the atmosphere; automatic rack shut-off means for closing communication between a rack and said source of gas material when a desired nal cylinder pressure is reached; full-cylinder indicating means including a signal for each of said racks for indicating when the desired cylinder pressure is reached; and control means adapted, when actuated, to operate said 4blowdown means to' release gas from the proper rack, to shift said cylinder evacuating means from one rack, and to shift said cylinder filling V means to said last-named rack; said racks being arranged so that at least Vone filled cylinder may be replaced by at least one empty cylinder on each rack, following each actuation of said control means, in a predetermined sequence.

2. Apparatus for filling gas storage cylinders to a desired final pressure comprising, in combination, a plurality of cylinder racks, cylinder evac-v back-pressure valve between said 'device and said rack for initially charging at least one cylinder connected to said rack with said gas material at a very rapid rate until the cylinder pressure reaches a value near the desired final pressure, and a relatively low-capacity connection for finally causing the gas material to flow at a very slow rate until the cylinder pressure reaches the desired value; rack blowdown means including means for selectively opening at least one of said racks `to the atmosphere; automatic rack shut-off means for closing communication in said lowcapacity connection between a rack and said source of gas material when a desired final cylinder pressure is reached; full-cylinder indicating means including a signal for each of said racks for indicating when the desired cylinder pressure is reached; and control means adapted, when actuated, to operate said blowdown means to release gas from the proper rack, to shift said cylinder evacuating means from one rack, and to shift said cylinder filling means to said lastnamed rack; said racks being arranged so that at least one lled cylinder may be replaced by at least one empty cylinder on each rack, followw ing each actuation of said control means, in a predetermined sequence.

3. Apparatus for lling gas storage cylinders comprising, in combination, a cylinder rack, cylinder evacuating means including means for con-v u for said rack for indicating the operation of shu oif means; and common control means for operating said cylinder evacuating means to connect said rack to a vacuum pump, for operating said cylinder filling means to connect said rack to a 'source of gas material under pressure, and for operating said rack blowdown means to open said rack to the atmosphere, in response to each actuation of'said common control means.

4. Apparatus for filling gas storage cylinders as claimed by claim 3, wherein said meansfor connecting said rack to a source of gas material under 'pressure comprises a relatively high-capacity connection for initially charging a cylinder connected to said rack with said gas material at a very rapid rate until the cylinder pressure reaches a value slightly below the desired nal pressure, and a relatively low-capacity connection for finally charging such cylinder with said gas material at la very slow rate until'tlie cylinder pressure reaches the desired final value.

5. Apparatus for filling gas storage cylinders comprising, in combination, four-cylinder racks each having two flexible conduits terminating in quick connectors for connecting a pair of cylinders to each rack; cylinder evacuating means including means for selectively connecting any two of said racks to a vacuum pump; cylinder filling means including means for selectively connecting any one of said racks to a source of gas material .under pressure; rack blowdown means for selectively opening any one of said racks to the atmosphere; a signal operatively associated with each of said racks for indicating when the cylinders connected thereto are filled with said gason each rack, following each actuation of said` control means, in a predetermined sequence.

6. Apparatus for filling gas storage cylinders to a desired final-pressure comprising, in combination. a cylinder rack; a constant-temperature controlling device having inlet meansrconnected to a source of gas material the pressure of which is 'greater than the desired final cylinder pressure; a relatively high-capacity connection between said device and said rack for initially charging at least one cylinder connected to said rack with said gas material at a very rapid rate until the cylinder pressure reaches a value near the desired final pressure; and a relatively lowcapacity connection between said device and said rack for finally causing the gas material to now through said rack at a very slow rate until the cylinder pressure reaches the desired final value, said low-capacity connection being in parallel relation with said high-capacity connection.

7. Apparatus for filling gas storage cylinders to a desired final pressure comprising, in combination, a cylinder rack; a constant-temperature controlling device having inlet means connected to a source of gas material the pressure of which is greater than the desired vfinal cylinder pressure; a relatively high-capacity connection including a back-pressure valve between said device and said rack for initially charging at least one cylinder connected to said rack with said gas 12 material at a very rapid rate until the cylinder pressure reaches a value slightly below the desired final pressure, and a relatively low-capacity connection between said device and said rack for finally causing the gas material to ow into said.

cylinder at a very slow rate until the cylinder pressure reaches the desired final value.

8. Apparatus for filling gas storage cylinders to a desired final pressure comprising, in combination, a cylinder rack; cylinder filling means including means for connecting said rack to -a source of gas material under pressure which is greater than the desired final cylinder pressure; said connecting means comprising a relatively high-capacity connection for initially charging a cylinder connected to said rack with said gas material at a very rapid rate until the cylinder pressure reaches a value slightly below the desired final pressure, and a relatively low-capacity connection in parallel with said high-capacity connection for finally charging such cylinder connected to said rack with said gas material at a very slow rate until the cylinder pressure reaches the desired final value.-

9. The method of evacuating and filling gas storage cylinders of the type having a cylinder valve, which comprises opening the cylinder valve f and evacuating each cylinder while the cylinder valve remains open, rapidly charging each cylinder with gas from a source the pressure of which is substantially higher than a desired final pressure of the gas within the filled cylinderby a relatively high rate of gas iiow through said cylin- I der valve until the pressure of the gas within said cylinder reaches a predetermined value which is slightly different from that vof said desired final pressure; then, while the cylinder valve remains open, slowly changing the gas pressure within said cylinder by a substantially reduced rateof gas flow through said cylinder valve until the pressure of the gas within said cylinder reaches the desired value; and thereupon closing said cylinder valve.

10. The method of evacuating and filling gas storage cylinders as claimed by claim 9, in which rapid charging of the cylinder is stopped'when the pressure of the gas within said cylinder reachesa predetermined value which is slightly below that of the desired final pressure and a small volume of gas is added to the cylinder at a comparatively low rate of flow immediately after it has been charged rapidly to said predetermined value.

'11. 'I'he method of filling a number of gas storage cylinders which comprises connecting a pair of cylinders to each of four racks; opening the rst and second racks to a vacuum pump; after the cylinders connected t0 said rst and second racks are evacuated, substantially simultaneously closing said first rack to said vacuum pump, opening the third rack to said vacuum pump, and opening said first rack to a source of gas matelrial under pressure; after the cylinders connected after the cylinders connected to said second rack u are filled, substantially simultaneously closing said second rack to said source, closing said third rack to said vacuum pump, opening said first rack to said vacuum pump, 'and opening said third rack to said source; and repeating the last two steps for each rack until all of the cylinders have been filled with said gas material.

12. The method of filling a number of gas storage cylinders with gas' material to a desired final pressure, which comprises connecting a plurality of cylinders to each of a plurality of racks; opening the first and second racks to a cylinder evacuating line; after the cylinders connected to said first rack are evacuated, substantially simultaneously closing said first rack to said evacuating line, opening the third rack to said evacuating line, and opening said first rack to a cylinder filling line; after the cylinders connected to said first rack are filled, substantially simultaneously closing said first rack to said filling line, closing mulator connected to said lling line, a backpressure valve in said filling line; four racks each having two cylinder connections, means including a filling valveconnecting each of said racks to said back-pressure valve, a rack blowdown valve connected to each rack, a gauge for indieating cylinder pressure, an equalizing line con nected to said gauge, means including a metering orice and a shut-off valve connecting said equalizing line to said filling line, means including an equalizin-g valve connecting each rack to said equalizing line, a cylinder evacuating line adapted to be connected to aV vacuum pump, means including an evacuation valve connecting each rack to said evacuating line, and means connecting said filling, blowdown, equalizing and i evacuation valves for operation in pairs so that said second rack tosaid evacuating line, opening the fourth rack to said evacuating line, and opening said second rackto said filling line; replacing the filled cylinders on said first rack with empty cylinders; and repeating the last two steps for each subsequent rack until all of the cylinders have been filled.

13. A four-rack two-cylinder method of lling a number of gas storage cylinders with gas material to a desired final pressure, which comprises, l

closing a rst rack to a cylinder evacuating line to which a second rack is also opened, opening a third rack to said evacuating line, and opening said first rack to a cylinder filling line; closing said first rack to said filling line, closing said second rack to said evacuating line, opening a fourth rack to said evacuating line to which said third rack is also opened, and opening said second rack to said filling line; replacing the filled cylinders on said rst rack with empty cylinders; closing said second rack to said filling line, closing said third rack to said evacuating line, opening said first rack to said evacuating line to which said fourth rack is4 also opened, and opening said third rack to said filling line; replacing the filled cylinders on said second rack with empty cylinders, closing said 'third rack to said filling line, closing said fourth rack to said evacuating line, opening said second rack to said evacuating line to which said first rack is also opened, and opening said fourth rack to said filling line; replacing the filled cylinders on said third rack with empty cylinders; closing said fourth rack to said filling line, closing said first rack to said evacuating line,

opening said third rack to said evacuating line to which said second rack is also opened, and opening said first rack to said filling line; replacing the filled cylinders on said fourth rack with empty cylinders, and repeating such cycle until all of the cylinders have been lled.

14. A four-rack two-cylinder system for filling gas storage cylinders with gas material to a deperature controlling device `for maintaining at a' substantially constant value the temperature of the gas delivered by said filling line, a gas accuwhile one pair of cylinders is being rapidly filled, a second pair of cylinders is completing a final period of evacuation, a third pair is completing an initial period of evacuation, and the fourth pair is being topped olf, the rack blown down, and the filled cylinders replaced with empty cylinders.

15. A four-rack two-cylinder system of filling gas storage cylinders with gas material to a desired nal pressure, Vcomprising four racks each having a pair of cylinder connections, a filling valve, an equallzing valve, an evacuation valve, a blowdown valve, and a full-cylinder signal lamp; a high-capacity cylinder lling line connected to the filling Valves; a low-capacity cylinder filling line containing a shut-olf valve connected to the equalizing valves; a cylinder evacuating line connected to the evacuation valves; a normally-open switch responsive to the pressure of said equalizing line and adapted to close when the cylinder pressure reaches a predetermined value, a main operating shaft having a handle: a coiled spring having one end connected' to said shaft; a clutch havingva first member loosely mounted on said shaft and connected to the other end of said spring, and a. second member connected to said shaft; gear and cam means ing stems for connecting the blowdown valves the equalizing valves to said second clutch rr ber; gear and cam means including stems for connecting the llingvalves and the evacuation valves to said first clutch member; means for locking said equalizing and blowdown valve stems and said shafbagainst reverse rotation every degrees by said.` spring; means including a latch for normally holding said filling and evacuation valve 'stems against forward rotation by said spring; means including a solenoid for releasing said latch to cause said spring to turn said filling and evacuation valve stems through 90 degrees; electric circuit means including said signal lamps, said switch and said solenoid for energizing said solenoid to release said latch when said switch is flrstclosed and to close said shut-off valve and illuminate one signal lamp when said switch is again closed; and means including cam means connected to said shaft for resetting said electric GEORGE H. SMITH. 

